This invention relates to a method for refining a methylnaphthalene-containing oil which is capable of removing sulfur compounds contained in the oil. This invention also relates to a method for refining a methylnaphthalene-containing oil which is capable of removing nitrogen compounds contained in the oil together with the sulfur compounds.
Methylnaphthalene is useful as a solvent, dye carrier, heat medium and the like, and also, as a starting material for synthesizing vitamin K.sub.3, and 2,6-naphthalenedicarboxylic acid, which is a starting material for various resins such as polyesters. In particular, methylnaphthalene having a low content of the sulfur compound is required for the production of vitamin K.sub.3 and 2,6-naphthalenedicarboxylic acid.
Japanese Patent Application Kokai No. 3(1991)-74336 proposes an improved process for refining a methylnaphthalene-containing hydrocarbon oil wherein sulfur compounds are removed from the hydrocarbon oil by hydrodesulfurizing the hydrocarbon oil in the presence of a catalyst containing molybdenum and nickel or molybdenum and cobalt on an aluminum support under the conditions including a pressure of ordinary pressure to 9.9 kg/cm.sup.2.